We wish to carry out a multifaceted investigation on normal and atypical melanocytes with major emphasis on the following topics: 1. A careful and in depth study on receptors for MSH on the surface of melanoma cells. 2. The localization of adenylate cyclase on pigment cells. 3. A genetic and biochemical analyses of the growth and melanization of melanoma cells. 4. The role of nuclear nonhistone proteins in the genetic expression of melanocytes. 5. Isolation and analysis of C-type viral particles from melanoma cells. 6. The role of microtubules and 100 Angstrom units filaments on the translocation of melanosomes. 7. Pigment cells in relation to the immune system. 8. Novel approaches to the chemotherapy of melanomas. Bibliographic references: Pawelek J, Sansone M, Koch N, Christie G, Halaban R, Hendee J, Lerner AB and Varga JM. Melanoma cells resistant to inhibition of growth by melanocyte stimulating hormone. Proc Nat Acad Sci USA 72: 951, 1975. Laties AM and Lerner AB. Iris colour and relationship of tyrosinase activity to adrenergic innervation. Nature 255: 152, 1975.